I just found out that TAudioConverter, although it has SoX support, uses ffmpeg for bitdepth changes, resampling, and dither. I don't use those functions very much, but I'm curious if anyone has done a quality comparison between the two.

Letís, er, letís hope FFmpeg has evolved by leaps and bounds since that version was released only about half a year ago.

It has, it now uses SoX

QUOTE

January, 7, 2013, FFmpeg 1.1We have made a new major release (1.1) It contains all features and bugfixes of the git master branch. A partial list of new stuff is below:...- SOX Resampler support in libswresample

Letís, er, letís hope FFmpeg has evolved by leaps and bounds since that version was released only about half a year ago.

Well, FFmpeg is now up to version 1.1.1, and Peter has incorporated it into fb2k, so I think we can assume the program's improved. Whether it's improved for this functionality is another question. Of course, there's a 14.4.1 version of SoX just out, too.

I did notice the large disparity in version numbers between 0.10.4 and now, but I found that 0.10.6 was released as recently as October, so I had to emphasise that the resampling may or may not have had the massive improvements that it so blatantly needs.

Edit: I just saw bandpass’s post, which I missed due to jkauff posting in the interim. Phew! That’s a relief.

Well, FFmpeg is now up to version 1.1.1, and Peter has incorporated it into fb2k, so I think we can assume the program's improved. Whether it's improved for this functionality is another question. Of course, there's a 14.4.1 version of SoX just out, too.

Oddly, SoX itself is a little behind the curve: 14.4.1 contains the same (slow, by comparison) version of the resampler that's been there for some years, so until SoX 14.5 is released (couple of months I think), the ffmpeg route will give better performance (about 2-3 x faster).

Don't know if it made it into 1.1.1 or not, but I saw that ffmpeg has also recently ported (most of) SoX's dither code.

Letís, er, letís hope FFmpeg has evolved by leaps and bounds since that version was released only about half a year ago.

Quoting the FAQ:

QUOTE

Are most SRCs really that bad?No. If you look at the decibel scale to the right from the graphs, you can see that the range of these graphs is very wide: down to -180 dB. The distortions generated by most properly designed SRCs are below -100 dB and can hardly create audible artifacts. However SRCs differ in the transition band of the low-pass filter and in the amount of pre-/post-echo and aliasing. The bottom line is that most tested SRCs range from fairly good to excellent, but the graphs are very sensitive to emphasize the differences.

Seems to me that those reflections of the actual input signal may still be quite a bit above –96 dB. Does that fall within the remit of “properly designed SRCs”? Even the background static does not look far below –100 dB.

Besides, even if that explanation were applicable, is it really anything other than hand-wringing when there is no real excuse for the algorithm to perform to such a poor standard? Other free programs can resample with many, many times less noise. Why give a free pass to some SRCs just because their distortions might not be audible? Again: “might”.

I thought this was a site that focusses on perceptual quality, sure, but doesn’t skimp on theoretical quality when there’s no good reason to do so.

the noise floor on a CD is around -110 dB, considering that the spectrogram display shows a power spectral density, not the waveform level. So, the regular 16-bit dithering noise is actually represented by this color. Here is the graph of the CD noise floor with a standard TPDF dither:

I'm curious though, why are some so bad? It doesn't look like anyone should need to reinvent the wheel so to speak, as there are amazing open-source (SoX) and proprietary (Adobe Audition) options, and hell, even Apple CoreAudio from 5 years ago is decent.

Highest setting of Apple CoreAudio resampler has really (unnecessarily) high SNR, but is 10x or more slower than SoX (at least on Windows).And even Microsoft resampler of Windows Media Foundation (CLSID_CResamplerMediaObject) has reasonablly good quality / performance, but read this bug on Win7 WaveOut:http://www.hydrogenaudio.org/forums/index....st&p=788882It seems that their left hand doesn't know what the right hand is doing.